PROJECT ABSTRACT The risk for anal cancer in HIV-positive individuals is up to 80-times higher than the general population with the incidence among HIV-positive men ranging between 49-131/100,000 person-years which is higher than the incidence of cervical cancer prior to universal screening with cervical cytology. Even though anal cancer prevention can be achieved with human papillomavirus vaccination, those who are currently at highest risk for anal cancer have already been exposed to HPV and remain at high risk for anal dysplasia/cancer. Thus, identifying best-practices for anal cancer prevention through anal dysplasia screening in HIV-positive individuals would be beneficial. However, acceptance of anal cytology as the gold standard for screening has not been universally recognized due to issues related to cost-effectiveness, reliability and accuracy. Current guidelines recommend high resolution anoscopy (HRA)-guided biopsies as a follow-up to abnormal anal cytologies although HRA is invasive with potential downsides including patient discomfort and anxiety associated with biopsies. Therefore, identifying less-invasive screening paradigms could revolutionize anal cancer screening programs in this vulnerable population. The project will adapt a novel technology, Raman- enhanced spectroscopy (RESpect), which is a laser-based tool that characterizes chemical molecular composition of cells and tissue. The study builds upon preliminary data which demonstrated unique RESpect fingerprints of anal dysplastic tissues from normal to low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL). Because standard RESpect protocol requires HRA-guided biopsies to obtain anal tissue to identify RESpect signatures in the laboratory, an innovative approach will adapt a novel portable fiber-optic RESpect probe to assess real-time screening and diagnosis. The central hypotheses are: 1) RESpect fingerprints will characterize a spectrum of anal dysplasia/cancer in HIV-positive individuals; and 2) RESpect fingerprints obtained by a portable probe are comparable to standard RESpect signatures obtained by the RESpect instrument. The novel proposal will translate RESpect technology to anal histologies from screening/diagnosis to potential clinical translational applications. The significance of the study lies in contributing new knowledge and identifying novel RESpect fingerprints as biomarkers in HIV-associated anal dysplasia/cancer which synergizes knowledge with technology to improve screening to improve healthcare delivery.